The present disclosure relates to a fixing device and an image forming apparatus.
Fixing devices using a heating film have been known to be included in electrographic image forming apparatuses. A fixing device such as above includes a fixing assembly and a pressure roller that presses against the fixing assembly to form a fixing nip part. The fixing assembly includes a tubular fixing film, a heater in contact with an inner surface of the fixing film, a heat insulating holder that holds the heater, a metal stay that presses the heat insulating holder against the pressure roller, a thermistor, and a thermal conduction member. The thermistor is provided on the heat insulating holder and in contact with the thermal conduction member at a specific pressure through a through hole in the heat insulating holder. The thermal conduction member is held by the heat insulating holder between the heater and the heat insulating holder.
Each of the heater, the heat insulating holder, the metal stay, and the thermal conduction member extends in a direction perpendicular to a recording medium conveyance direction. In a state in which the metal stay is attached to the heat insulating holder, the load of the metal stay is transmitted to the heat insulating holder in a longitudinal direction of the heat insulating holder via pressure springs disposed at opposite ends of the metal stay in the longitudinal direction of the metal stay. Heat accumulated in a paper non-passing area of the fixing nip part is transmitted to the thermistor via the thermal conduction member. In the fixing device, an excessive increase in temperature of the paper non-passing area can be suppressed.